Stock mufflers.....

[V-twin]

Has any one cut open the stock mufflers and re-cored them? 

[TAftonomos]

I hate when people do this, but I'm going to join them.

Search.  There are several threads on chopping the cans.  Pretty easy, and plenty of people have done it 

[V-twin]

Yep thanks TAftonomos, swampduc already told me too....  sorry I will do a search